PyGameZero：不同级别的背景图像可能不同吗？

Question

我正在用python和pygame zero创建一个小游戏。在游戏中，我喜欢使用不同的背景图像为不同的水平。因此，如果用户达到2级，就会出现一个新的背景图像。这可能吗。我试过了，但总是收到错误信息：“pygame.error错误：无法打开images\background2.png”。路径100%正确。这是我的完整代码：

from random import randint
import pygame

WIDTH   = 800
HEIGHT  = 800

apple = Actor("apple")
apple.pos = randint(0, 800), randint(-800, 0)

pear = Actor("pear")
pear.pos = randint(0, 800), randint(-800, 0)

plum = Actor("plum")
plum.pos = randint(0, 800), randint(-800, 0)

donut = Actor("donut")
donut.pos = randint(0, 800), randint(-800, 0)

ice = Actor("ice")
ice.pos = randint(0, 800), randint(-800, 0)

chips = Actor("chips")
chips.pos = randint(0, 800), randint(-800, 0)

burger = Actor("burger")
burger.pos = randint(0, 800), randint(-800, 0)

happysmiley = Actor("happysmiley")
happysmiley.pos = 300, 750

start = Actor("start")
start.pos = 700,750

quitgame = Actor("quit")
quitgame.pos = 600, 750

creditsinfo = Actor("credits")
creditsinfo.pos = 485, 750

back = Actor("back")
back.pos = 600, 100

nextlevel = Actor("nextlevel")
nextlevel.pos = 700, 750

gameover = False
score = 0
gamemode = 1
gamestart = 0
level = 0

background = pygame.image.load("images\\background.png")
background2 = pygame.image.load("images\\background2.png")

pygame.mixer.init()
pygame.mixer.music.load("music\\funmusic.mp3")
pygame.mixer.music.play(-1)

def draw():
    global gamemode
    screen.clear()
    if gamemode == 0 and score >= 100:
        endoflevel1()
    else:
        drawgame()

    if gamemode == 3 and score >= 150:
        endoflevel2()


def drawgame():
    global gamemode

    if gamemode == 1:
        screen.clear()
        screen.blit("background",(0,0))
        apple.draw()
        pear.draw()
        plum.draw()
        donut.draw()
        ice.draw()
        chips.draw()
        quitgame.draw()
        happysmiley.draw()
        start.draw()
        creditsinfo.draw()
        screen.draw.text("Punkte: " + str(score), (700, 5), color = "black")

    elif gamemode == 0:
        screen.clear()
        screen.blit("background",(0,0))
        apple.draw()
        pear.draw()
        plum.draw()
        donut.draw()
        ice.draw()
        chips.draw()
        happysmiley.draw()
        screen.draw.text("Punkte: " + str(score), (700, 5), color = "black")

    elif gamemode == 2:
        screen.clear()
        screen.fill("orange")
        back.draw()
        screen.draw.text("Credits", topleft=(350,10), fontsize=40)
        pygame.display.flip()

    elif gamemode == 3:
        screen.clear()
        screen.blit("background2",(0,0))
        apple.draw()
        pear.draw()
        plum.draw()
        donut.draw()
        ice.draw()
        chips.draw()
        burger.draw()
        happysmiley.draw()
        screen.draw.text("Punkte: " + str(score), (700, 5), color = "black")

def update():
    global score, gamestart

    if gamestart == 1:

        if score >= 100:
            pygame.mixer.music.stop()
            return

        if apple.y < 800:
            apple.y = apple.y + 4
        else:
            apple.x = randint(0, 800)
            apple.y = randint(-800, 0)

        if pear.y < 800:
            pear.y = pear.y + 4
        else:
            pear.x = randint(0, 800)
            pear.y = randint(-800, 0)

        if plum.y < 800:
            plum.y = plum.y + 4
        else:
            plum.x = randint(0, 800)
            plum.y = randint(-800, 0)

        if donut.y < 800:
            donut.y = donut.y + 4
        else:
            donut.x = randint(0, 800)
            donut.y = randint(-800, 0)

        if ice.y < 800:
            ice.y = ice.y + 4
        else:
            ice.x = randint(0, 800)
            ice.y = randint(-800, 0)

        if chips.y < 800:
            chips.y = chips.y + 4
        else:
            chips.x = randint(0, 800)
            chips.y = randint(-800, 0)

        if keyboard.left:
            happysmiley.x = happysmiley.x - 5
        elif keyboard.right:
            happysmiley.x = happysmiley.x + 5

        if happysmiley.collidepoint (apple.x, apple.y):
            score = score + 2
            effect = pygame.mixer.Sound("sounds\\bonus.wav")
            effect.play()
        if happysmiley.collidepoint (pear.x, pear.y):
            score = score + 1
            effect = pygame.mixer.Sound("sounds\\bonus.wav")
            effect.play()
        if happysmiley.collidepoint (plum.x, plum.y):
            score = score + 1
            effect = pygame.mixer.Sound("sounds\\bonus.wav")
            effect.play()
        if happysmiley.collidepoint (donut.x, donut.y):
            score = score - 1
            effect = pygame.mixer.Sound("sounds\\no.wav")
            effect.play()
        if happysmiley.collidepoint (ice.x, ice.y):
            score = score - 1
            effect = pygame.mixer.Sound("sounds\\no.wav")
            effect.play()
        if happysmiley.collidepoint (chips.x, chips.y):
            score = score - 1
            effect = pygame.mixer.Sound("sounds\\no.wav")
            effect.play()

    if level == 2:
        if burger.y < 800:
            burger.y = burger.y + 4
        else:
            burger.x = randint(0, 800)
            burger.y = randint(-800, 0)


        if happysmiley.collidepoint (burger.x, burger.y):
            score = score - 1
            effect = pygame.mixer.Sound("sounds\\no.wav")
            effect.play()

def on_mouse_down(pos): # wurde Maustaste gedrückt?
    global score, gamestart, gamemode

    if start.collidepoint(pos):
        gamestart = 1
        gamemode = 0
    if quitgame.collidepoint(pos):
        exit()
    if creditsinfo.collidepoint(pos):
        gamemode = 2
    if  back.collidepoint(pos):
        gamemode = 1

def endoflevel1():
    global score, gamemode, gamestart, level
    screen.clear()
    screen.fill("green")
    screen.draw.text("Congratulations! You have successfully completed the 1st level!", topleft=(100,350), fontsize=30, color = "black")
    nextlevel.draw()  
    gamestart = 0
    pygame.display.flip()
    running = True
    while (running):
        for event in pygame.event.get():  
            if event.type == pygame.MOUSEBUTTONDOWN:
                if  nextlevel.collidepoint(event.pos):
                    score = 0
                    gamemode = 3
                    gamestart = 1
                    level = 2
                    running = False

def endoflevel2():
    global score, gamemode, gamestart, level
    screen.clear()
    screen.fill("orange")
    screen.draw.text("Congratulations! You have successfully completed the 2nd level!", topleft=(100,350), fontsize=30, color = "black")
    nextlevel.draw()  
    gamestart = 0
    pygame.display.flip()

完整的错误消息是：

Traceback (most recent call last):
  File "runpy.py", line 193, in _run_module_as_main
  File "runpy.py", line 85, in _run_code
  File "C:\Program Files\Programmierung\Mu\pkgs\pgzero\__main__.py", line 3, in <module>
    main()
  File "C:\Program Files\Programmierung\Mu\pkgs\pgzero\runner.py", line 92, in main
    exec(code, mod.__dict__)
  File "ninjatest2.py", line 53, in <module>
    background2 = pygame.image.load("images\\background2.png")
pygame.error: Couldn't open images\background2.png
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: cHRM chunk does not match sRGB